Periodontal disease is the most common cause of tooth loss in the adult human and it is therefore a massive public health problem. It is generally agreed that our best opportunity for solution of the problem lies in research aimed at prevention. One important aspect of this research is investigation of the response of the host's tissues to the etiologic agent(s) responsible for the disease. There is a large body of evidence supporting the concept that the production, maturation and maintenance of collagenous component of the periodontium may play a vital role in the function of the normal periodontium, and that derangement of the collagenous component is an event of major importance in the development of periodontal disease. In spite of the evidence that collagen alterations are an important component of periodontal disease, the biochemical characteristics of collagen in the periodontal tissues have not been studied in either the normal or abnormal states. This is somewhat surprising in light of the massive amount of information available on collagens comprising skin, bone and other connective tissues. It is our chief objective to characterize the collagen(s) produced by the gingival cells and forming the ligaments of the marginal gingiva, and to determine the effects of plaque accumulation and developing periodontal disease upon these molecules. Achieving this aim will require the use of many of the techniques of modern cell biology and biochemistry including cell and tissue culture, and various preparative and analytical radiochemical and biochemical procedures. Successful completion of the proposed investigation will provide an insight into the mechanisms by which the accumulation of dental plaque leads to tissue alterations and eventual tooth loss.